Scientists have known about the Zika Virus for over half a century:
The virus was first identified in rhesus monkeys in Uganda in 1947, and in humans in 1952 in Uganda and Tanzania. In 2015, Zika outbreaks were confirmed in Brazil and Colombia.
Normally spread by mosquito bite, the virus can also be sexually transmitted. While the virus is most known for flu-like symptoms and conjunctivitis, we now know it can also lead to increased incidence of microcephaly (a smaller than expected head) in fetuses:
Ultrasonographic examination that was performed at 29 weeks of gestation showed the first signs of fetal anomalies, and she was referred to the Department of Perinatology. At that time, she also noticed reduced fetal movements. Ultrasonography that was performed at 32 weeks of gestation confirmed intrauterine growth retardation (estimated third percentile of fetal weight) with normal amniotic fluid, a placenta measuring 3.5 cm in thickness (normal size) with numerous calcifications, a head circumference below the second percentile for gestation (microcephaly), moderate ventriculomegaly, and a transcerebellar diameter below the second percentile.
Because of this increased risk of birth defects, Zika has been declared an international health emergency by the World Health Organization. Pregnant women are being warned against travel to areas where the virus is more common.